Intended to help upper elementary and secondary school teachers increase their students' critical thinking, this booklet discusses the theory and techniques behind the use of questioning to evoke prior knowledge and further inquiry. The first portion of the booklet discusses the theory and research that underlie the use of questioning, examining questioning hierarchies and how they are used. The second portion of the booklet puts this research into practice, by introducing the questioning circle--a Venn diagram of intersecting questions dealing with the subject matter, personal reality (prior learning), and external reality. The discussion adapts this structure to literature, language, and composition instruction. Managing classroom interaction, such as what to do when students cannot, do not, or will not answer, and dealing with short or wrong answers are then explored, and suggestions for encouraging student answers are supplied. The booklet concludes with a discussion on helping students generate their own questions to stimulate further critical thinking. (HTH)